Preheat your oven to 350°F and get those 2 pans (9″) prepped with parchment and butter.
In a big bowl, mix together flour, sugar, baking powder, baking soda, and salt.
Add eggs, oil, and buttermilk, and whisk until just combined.
Time for the magic touch – mix instant coffee with hot water and pour it into the batter. Give it a good stir.
Pour 1/3 of the batter into another bowl. Sift in the cocoa powder and gently fold it in.
Divide the original batter equally into the two pans. Spoon on the cocoa-flavored batter, then use a toothpick to create a cool marbled effect.
Bake for 25-28 minutes or until a toothpick comes out with moist crumbs. Let those beauties cool.
Time for the buttercream:
Whisk coffee, sugar, and water until they form a light-colored, thick mixture (we call it dalgona).
In another bowl, whisk butter and 1.5 cups of icing sugar until light and airy. Add the dalgona mix and keep whisking until you’ve got a smooth buttercream. Taste and tweak as needed.
Let’s assemble the masterpiece:
Once the cakes are cool, trim off the domes and cut each into two layers.
Layer them up on a cake stand with that delicious buttercream. Coat the top and edges generously.
Pop it in the fridge for an hour, then get ready to indulge! Enjoy!